Rotary engine

ABSTRACT

A fluid-driven rotary engine comprising a rotor forwardly rotatable about a central axis and a lobed stator defining an elongated forwardly extending arcuate fluid chamber therebetween which has a fluid inlet port adjacent the stator lobe and a fluid outlet port remotely forwardly of the inlet port. The rotor carries a resiliently depressible vanelike piston that extends from the rotor wall across the fluid chamber, the piston head portion sliding along the stator-wall including at the preferably arcuate apex of the stator lobe, the vanelike piston being resiliently depressible along a cavity axis that is decidedly nonradial with respect to the rotor central axis to ensure slidable contact of the piston along the entire stator wall. There are means to introduce steam or other fluid into the fluid chamber through the inlet port during brief intervals when the vanelike piston is forwardly passing the inlet port.

United States Patent {72] In entor Bernhardtstahmer 626,216 6/1899 Bodam 418/212 1509 Chicago, Omaha, Nebr. 68102 779,400 1/1905 Estby 418/258 {21] P 854330 Primary Examiner-Carlton R.Croyle [22] Filed Aug. 29, 1969 E J h J v brk Patented g 3 1971 Assistant xammero n ra l Attorney-George R. Nimmer [S4] ROTARY ENGINE laims,4 D in 1- 8 ABSTRACT: A fluid-driven rotary engine comprising a rotor U-s. forwardly rotatable about a central axis and a lobed stator 4l3/1454l8/233 defining an elongated forwardly extending arcuate fluid lnt. ..F0lc chamber therebetween has a inlet port adjacent F040 17/00, F049 27/00 the stator lobe and a fluid outlet port remotely forwardly of the inlet port The rotor carries a resiliently depresslble 145,236,238;9l/ 140 vanelike piston that extends from the rotor wall across the fluid chamber, the piston head portion sliding along the stator- [56] Rderences cited wall including at the preferably arcuate apex of the stator UNITED STATES PATENTS lobe, the vanelike piston being resiliently depressible along a 232,793 9/1880 Whitney 91/140 cavity axis that is decidedly nonradial with respect to the rotor 302,316 7/1884 Beystrum 418/144 central axis to ensure slidable contact of the piston along the 563,814 7/1896 Steinkoenig 91/140 entire stator wall. There are means to introduce steam or 651,616 6/1900 Thormeyer..... 91/140 other fluid into the fluid chamber through the inlet port during 747,418 12/1903 DHalewyn. 91 140 brief intervals when the vanelike piston is forwardly passing 3,374,943 3/1968 Cervenka 418/145 the inlet port.

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a as 42 m \\\41 27 l R 1 43 3e \\19 1e-- g Patented Aug. 3, 1971 3,597,132

4 Sheets-Sheet 1 1 1 BERNHARDT SI'AHMER INVENTOR.

ATTO NEY Patented Aug. 3, 1971 3,597,132

NNNNNN OR fin V2272 x H A Patented Aug. 3, 1971 3,597,132

4 Sheets-Sheet 4.

FIG. 4

BERNHARDT STAHMER I NVENTOR.

ROTARY ENGINE The prior art teaches fluid-driven rotary engines comprising a rotor forwardly rotatable about a central axis and a stator defining an elongate arcuate fluid chamber disposed between the circular rotor wall and the stator wall, said fluid chamber extending forwardly of a fluid inlet port which port is located adjacently forward ofa stationary partition wall (such as a stator lobe), the wall providing a rearward terminus for the fluid chamber. The rotor carries a vanelike piston having a head end in slidable contact with the stator-wall as the relatively high pressure fluid in the fluid chamber drives the piston and associated rotor forwardly about the central axis, said piston commonly being resiliently depressible toward the rotor wall to clear the partition wall at the chamber rearward end. However, such generically defined fluid-driven rotary engines of the prior art are deficient in many respects, the most notable deficiencies being with respect to the piston performance and reliability at high engine speeds and when exceedingly high pressure fluids (such as steam) are employed.

It is accordingly the general object of the present invention to provide an improved fluid-driven rotary engine which overcomes the several disadvantages and deficiencies of prior art rotary engines.

It is a specific object to provide an improved fluid-driven rotary engine which is adaptable for reliable performance with a wide range of rotor speeds and with a number of selectable high pressure fluids as the motivating power including: various liquid fluids such as oils; various gaseous fluids such as vaporized water in steam form and halogenated hydrocarbons; and even as combustible gaseous fuels such as mixtures of hydrocarbons and oxygen, in which case a fuel ignition means is required.

It is another object to provide a fluid-driven rotary engine having a resiliently depressible vanelike piston carried by the rotor and slidable along the entire stator wall, wherein the vanelike piston is long lasting and of reliable performance including ensurance that the piston will remain in firm slidable contact with the stator wall for the entire rotor revolution.

It is a specific object to provide a steam-driven rotary engine that is reliable in operation, exceedingly efficient, of low cost, and that is adaptable for a wide range of use conditions including for a motor vehicle power plant.

It is a further object to provide a fluid-driven rotary engine that is adaptable for one or more sets of pistons and fluid chambers for a single rotor and which is further adaptable to a bank of rotors disposed consecutively along the same central axis of rotation.

With the above and other objects and advantages in view, which will become more apparent as the description proceeds, the fluid-driven rotary engine E of the present invention comprises: a central shaft disposed along a central axis .A" serving as a focal reference point for the engine, said central shaft being continuously forwardly rotatable about the central reference axis; a rotor member R" attached to and directly revolvable with the central shaft 10, said rotor R" including a rotor wall completely surrounding the central axis, said rotor wall at any plane perpendicular to the central axis being spaced a constant radial distance from the central axis A," said rotor being provided with at least one elongate cavitate portion commencing at the rotor wall and extending along a nonradial cavity axis C; a stator member 8" having a peripheral stator wall that nonconcentrically surrounds the central axis, the major portion 31 of the stator wall being spaced radially from the rotor wall to provide a forwardly arcuately extending fluid chamber F," a minor portion of the stator wall being as a stator lobe in slidable contact with the rotor wall to define the rearward extremity of the fluid chamber; a fluid outlet port 39 at the forward portion of the fluid chamber; a fluid inlet port 38 disposed at the rearward portion of the fluid chamber; a headed vanelike piston disposed within the rotor cavitate portion 25 along the nonradial cavity axis C, said vanelike piston being resiliently depressible into the rotor cavitate portion 25 along the cavity axis whereby the piston head remains in slidable contact with the stator wall 30; and means for admitting finite quantities of engine motivating fluid into the fluid chamber F" through the inlet port 38as the vanelike piston forwardly passes the inlet port.

In the drawing, wherein like characters refer to like parts in the several views, and in which:

FIG. I is a forward elevational view of a representative embodiment of the fluid-driven rotary engine of the present invention.

FIG. 2 is a sectional elevational view taken along line 22 of FIG. 1.

FIG. 3 is a sectional elevational view taken along line 3-3 of FIG. 2.

FIG. 4 is a sectional elevational detail view taken along lines 4-4 ofFlGS. l and 3.

The fluid-driven rotary engine E" of the present invention comprises a central shaft 10 disposed along a central axis A," said axis A" serving as a focal reference point for the rotor wall 20 and for the stator wall major arcuate portion 31. Central shaft 10 is continuously rotatable in at least one of the two angular directions about central axis A, the said chosen angular direction being arbitrarily denominated as the forward direction and herein specifically as the arrowed clockwise direction of FIGS. 1 and 3.

Rotor member R" is attached to central shaft 10, as by means of keyed lug 11, to rotor R whereby the said rotor is directly revolvable with central shaft 10, rotor R also rotating in the said forward angular direction and herein clockwise as in FIGS. 1 and 3. The rotor wall 20 concentrically surrounds central axis A," and as typified by FIG. 3, rotor wall 20 at any plane perpendicular to central axis A" is spaced a constant distance from said axis. Specifically herein, rotor R" has an outer cylindrical rotor wall 20. Rotor R" has a pair of parallel upright end walls including forward wall 22 and rearward wall 23, said upright walls 22 and 23 each being perpendicular to central axis A.

Rotor R" is provided with at least one elongate cavitate portion 25 commencing at rotor wall 20 and extending along a linear cavity axis C, said cavitate portions 25 having an inward terminus 26 remote of rotor wall 20. Cavity 25 in cross section perpendicular to cavity axis C is of regular size and geometrical shape (herein rectangular) commencing at rotor wall 20. Cavity axis C" is nonradial with respect to central axis A. The designation a nonradial cavity axis is defined to mean that cavity axis "C" when indefinitely extended does not intersect central axis A, and at its closest proximity to axis A," the proximal distance D of cavity axis C from axis A" bears a ratio of at least about one-fourth with respect to the constant radial distance of rotor wall 20 with respect to axis A. Ofcourse, the proximal distance D" would be measured along a line perpendicular to cavity axis C" and intersecting axis "A" in a plane perpendicular to axis A as typified in FIG. 3. Moreover, the preferable situation wherein stator 8" including stator wall 30 surrounds rotor wall 20, the proximal distance D" bears a ratio of less than about threefourths with respect to the constant radius of rotor wall 20. Herein, two cavitate portions 25 are employed with the two cavity axes C" being parallel to each other and spaced on opposite sides of axis A." If three or more rotor cavitate portions would be employed, the respective cavity axes would provide an imaginary regular polygon with axis A at the geometric center thereof.

Stator S has peripheral stator wall 30 that completely nonconcentrically surrounds central axis A, the major portion 31 of stator wall 30 being spaced a constant distance from rotor wall 20 and from axis A" whereby a forwardly arcuately extending fluid chamber F" is defined by the radial space between rotor wall 20 and stator wall 30. Minor portions 32 and 33 of stator wall 30 converge inwardly from respective terminii of major portion 31 to rotor wall 20 to provide a stator lobe 34 having an arcuate apex 35 in slidable contact with rotor wall 20 as rotor R" rotates forwardly. Stator wall minor portion 32 extends abruptly from lobe apex 35 to stator wall major portion 31, said portion 32 providing the leading or rearward portion of fluid chamber F" with slidable apex 35 being the fluid chamber leading end. Stator wall minor portion 33, which is forwardly remote of 32, provides the fluid chamber trailing or forward end. Stator wall'minor portion 33 is at least twice lengthier than stator wall portion 32 between 20 and 31, which provides the necessarily gentler slope for portion 33. Preferably herein, lobe apex 35 is arcuate in geometric similarity to rotor wall 20 and is thus spaced a constant radial distance from axis A. The arcuate length of lobe apex 35 is sufficiently broad to form an angle of 5 to axis A whereby the lengthy lobe apex 35 is slidable contact with rotor wall provides a fluid-impervious barrier between inlet port 38 and outlet port 39, and thus, ensuring that fluid introduced through inlet port 38 must travel the full length of fluid chamberF" prior to its exhaust through outlet port 39.

The housing for fluid-driven rotary engine E" herein comprises he opposed upright stationary end plates 12 and 13 which are held above an underlying substrate by suitable support means, such as the four legs 16-19 attached to and extending downwardly of end plates 12 and 13. Legs 16 and 17 are conveniently attached on respective sides of end plate 12 while legs 18 and 19 are similarly attached to end plate 13. Moreover, the end plates 12 and 13 are affirmatively attached to the intervening stator as by screws 74, and herein the stator 5" surrounds rotor R" whereby the inlet conduit 36 and outlet conduit 37 can be affirmatively attached to stator S on the external side of engine E". End plates 12 and 13 are each provided with bushings 8" surrounding axis A" to journal central shaft 10. The upright ends 22 and 23 of rotor R are parallel to end plates 12 and 13, respectively, and slidable with said end plates as rotor R" rotates. Upright end plates 12, 13 at rotor ends 22 and 23 are provided with circular gaskets 24 concentric about and annularly surrounding axis A and shaft 10, said circular gaskets 24 being disposed nearer to rotor wall 20 than to axis A" so as to prevent fluid leakage from chamber F" between rotor R" and end plates l2, 13 as rotor R rotates.

There is an outlet conduit 37 attached to stator 5" for the exhausting of fluid from the forward trailing portion of the arcuately elongate fluid chamber F said outlet conduit communicating with chamber F through outlet port 39. An inlet conduit 36 is attached to stator 5" for the introduction of fluid into the leading portion of said fluid chamber F", said inlet conduit communicating with chamber F through inlet port 38. lnlet conduit 36 has conventional fluid valve means V" therealong to control the amount and duration of fluid introduced into chamber "F". Valve means V" might take the form of a conventional on-oil type steam or liquid or gas valve (depending upon the type of fluid to be introduced into chamber F") and as might be actuated by an elongate control lever 28. For purposes of illustration, valve control lever 28 is shown in solid line in FIGS. 1 and 3 in the on position and in phantom line in the "off" position. A tension spring 29 is actuatably connected between control lever 28 and a stationary lug 14 on the stator "S" whereby valve V" is conveniently shown as a normally closed" type valve.

There is a vanelike piston 40 carried within each rotor cavity 25, each said vanelike piston 40 lying along a cavity axis C" and having an outward or head portion 41 at rotor wall 20, and an inward or backend 46, said piston backend 46 being disposed nearer to cavity inward end 26 than is the head portion 41. As can best be seen in F165. 3 and 4, there are spring means, herein as four transversely aligned coil springs 47, disposed between cavity inward end 26 and the piston backend 46 whereby piston 40 is resiliently depressible along cavity axis C" and the piston head portion 41 is constantly urged against stator wall 30 as rotor "11 rotates, However,

piston 40 is sufficiently resiliently depressible along cavity axis allow piston 40 to pass the stator-lobed portion 34. As can best be seen in FIG. 2, the piston head portion includes a forwardly extending tip 42, the forward free end extremity of which is disposed between walls 20 and 31, and further includes a rearwardly extending tip 43 having an upper side slidably disposed along stator wall 30 and having a lower side disposed between walls 20 and 30. The cavity recess 27 at rotor wall 20 is dimensionally sufficient to accommodate members 42, 43 as piston 40 passes by stator lobe 34. There is herein a T-shaped gasket 44 removably disposed within a matching slotted portion of the piston head portion whereby actual slidable contact between piston 40 and stator wall 30 is afforded by expendable gasket 44.

Piston 40 is sufficiently transversely broad that its two upright ends brush alongside end plates 12, 13 and also alongside the gaskets 24 as rotor R rotates. Thus, when steam or other fluid is introduced into fluid chamber F" against the piston rearward side, eg at 43, the piston 40 which fully bridges the radial gap between walls 20 and 30 acts as a forwardly movable vanelike barrier to the forwardly traveling motive fluid, there being substantially zero fluid leakage between piston 40 and the end plates 12, 13 and stator wall 30.

1t is essential to the engine E of the present invention that there he means to admit fluid from inlet conduit 36 into a rearward portion of fluid chamber F" when the forwardly moving vanelike piston 40 and including its rearward extremity 43 is moving past inlet port 38. Moreover, the fluid is introduction into chamber "F for some finite duration but not to exceed the time required for the vanelike piston to reach a fluid-shutoff position." The term fluid-shutoff position" is defined to mean a position for piston 40 between inlet port 38 and outlet port 39, and preferably wherein the fluid volume disposed forwardly of the piston exceeds the fluid volume. disposed rearwardly thereof. when the fluid employed is steam, at the steam-shutoff position, the fluid volume forwardly of the piston would be a multiple factor of the fluid volume rearwardly thereof, as indicated in phantom line in F IG. 3. ln the steam engine embodiment, the fluid volume to the rear of piston 40 at the steam-shutoff position would include the volume of inlet conduit 36 between valve V and inlet port 38 together with the fluid chamber volume between lobe apex 35 and piston 40. I

Timed fluid introduction into chamber F as required in the preceding paragraph can be accomplished inmany ways, depending upon the precise fluid valve V" chosen, but merely for the purposes of illustration, the cam-actuated connector rod 55 will be arbitrarily chosen and described. Cam 51 having the type of contour illustrated in FIG. 1 surrounds central shaft 10 remote of housing end plate 12, cam 51 being attached to shaft 10 by setscrew 52. (Jam 51 is herein dual-lobed appropriate to the engine embodiment shown in the drawing which has two fluid chambers F" and two fluid inlet conduits 36. Elongate connector rod 55 is provided with an elongate axial slot 56, and connector rod 55 is reciprocatably attached to housing end plate 12 with guide pins 57 and 58 which are slidably engaged with connector rod 55 along the axial slot 56 thereof. The first of the two ends of connector rod 55 abuttably rides along the contour of cam 51, while the connec tor rod second end is attached to the valve means actuator'28 as by pivot pin 58, thus causing valve means "V" to admit fluid into chamber F at the appropriate time intervals.

Operation of the fluid-driven rotary engine E will now be described. Although either liquid or gaseous noncombustible fluids, or combustible gases with timed ignition, might be employed with equal facility through the inlet port to actuate the engine, vaporous water, i.e. steam, will be described herein as the pressured fluid motive power. Assuming as initial positions for elements 51, 55, 28, R", and 40, shown in the drawing, and with rotor R" moving in the forward clockwise direction, vanelike piston 40 has just forwardly passed inlet port 38 and stator wall minor portion 32 with piston rear tip 43 at the rearward end of stator wall major portion 31. The valve means V" is ideally actuated, as through its lever arm 28, at the precise moment when piston rear tip 43 is at the rearward end of stator wall major portion 31 as indicated in FIG. 3, whereupon high-pressure steam fluid is introduced through inlet port 38 into fluid chamber F". By virtue of the stator lobe barrier 34, 35, the introduced steam must necessarily travel generally forwardly and impinges against the piston rearward side including against rear tip 43. The fluid pressure against rearward tip 43 helps to ensure firm slidable contact of the piston headed portion 41 including gasket 44 against stator wall 30, and thus, serves to prevent piston 40 from binding within cavity 25. Steam continues to be introduced into chamber F as vanelike piston 40 reaches a "steam-shutoff" position, as indicated in phantom line in FlG. 3, whereupon valve V" is closed. The finite quantity of high pressure steam to the rear of vanelike piston 40 continues to expand, driving piston 40 and rotor R" forwardly past the forward extremity of stator wall major portion 31 whereupon at minor portion 33 piston 40 assisted by forward tip 42 is forced to move progressively closer to cavity inward terminus 26. Eventually, when piston 40 reaches the lobe apex 35, the piston headed portion 41 including tips 42, 43 is disposed within cavity 25 at rotor wall whereby the relatively low-pressure steam fluid is allowed to exhaust through port 39 and thence through outlet conduit 37. The momentum of rotor carries vanelike piston 40 past the arcuate lobe apex 35, and the resiliently depressible piston 40 is abruptly urged against stator wall major portion 31. The stator wall leading portion 32, being generally parallel to cavity axis C" helps to further ensure against binding of piston 40 within cavity 25. Moreover, the piston position along nonradial cavity axis C" prevents the piston head from binding against stator wall major portion 31 under the centrifugal force developed by high rotor speeds, centrifugal forces on piston 40 be exerted at least partially instead on the wall of cavity 25.

The illustrated engine has two vanelike pistons and two fluid chambers F whereby each revolution of rotor R" causes two of the aforesaid operating cycles to occur. It is, of course, possible to have one, or three, or four, or more sets of pistons and fluid chambers on each rotor stator unit depending upon design considerations. Moreover, two or more rotor stator units could be banked consecutively along axis A", each rotor stator unit to be separated by fluid-impervious separators, e.g. end plates 12 or 13. For such consecutive rotor stator units, thermodynamic efficiency could be increased by taking exhaust steam from the outlet conduit of the first unit, and introducing same as motive fluid into the inlet conduit of the second unit, etc., until the same steam under very low pressure is exhausted from the outlet conduit of the final rotor stator unit.

From the foregoing, the construction and operation of the fluid-driven rotary engine will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope ofthe appended claims.

l claim:

1. A rotary engine having a rotor member and a stator member and comprising:

A. A central shaft disposed along a central axis, said central axis serving as a focal radial reference point for the rotary engine, said central shaft being continuously rotatable in one of the two angular directions about said central axis, the said chosen angular direction being arbitrarily denominated as the forward direction;

8. A rotor member attached to said rotatable central shaft whereby said rotor is directly revolvable with respect to the rotatable shaft, said rotor in perpendicular cross section to the central axis having a rotor wall concentric about the central axis focal reference, the said rotor being provided with at least one elongate cavitate portion commencing at the rotor wall and extending along a linear cavity axis which when indefinitely extended does not intersect the central axis focal reference so that the closest proximity of the indefinitely extended cavity axis to the central axis bears a ratio of at least one-fourth with respect to the constant radius of the rotor wall, said cavitate portion terminating as an inside terminus remote of the rotor wall;

C. A stator member surrounding the central axis, said stator having a peripheral stator wall that completely nonconcentrically surrounds the central axis, the major length portion of said stator peripheral stator wall being spaced a constant distance from the rotor wall and from the central axis whereby a forwardly arcuately extending fluid chamber exists within the radial space between the rotor wall and the stator wall, minor portions of said stator wall defining a stator lobe extending radially toward the rotor wall and including a lobe apex in slidable contact with the rotor cylindrical wall, said stator lobe extending abruptly from its apex at the rotor wall to the stator wall major length portion to provide a leading portion of the fluid chamber and the apex provides the leading end extremity thereof, said arcuately extending fluid chamber having a trailing position forwardly remote of said stator lobe;

D. An outlet conduit attached to the stator for the exhausting of fluid from the forward trailing portion of the forwardly arcuately extending fluid chamber, said outlet conduit communicating with an outlet port within the fluid chamber trailing portion and disposed some finite angular distance forwardly of the fluid chamber leading end extremity;

E. An inlet conduit attached to the stator for the introduction of fluid into the fluid chamber, said inlet conduit communicating with an inlet port within the chamber leading portion and disposed less than said finite angular distance forwardly of the fluid chamber leading end, said inlet conduit including valve means to control the amount and duration ofa fluid power source for introduction into the fluid chamber;

F. A resiliently depressible vanelike headed piston carried by the rotor within the elongate cavitate portion and being resiliently urged along the cavity axis from the rotor wall toward the stator wall, the vanelike piston head portion including a rearwardly extending tip that is constantly urged against the stator wall as the rotor rotates, said vanelike piston being sufficiently resiliently depressible along the cavity axis so that the piston head extremity is positionable at the rotor wall when the vanelike piston is disposed at the apex of the stator lobe; and

G. Means to cause said inlet conduit valve to admit a fluid power source into the fluid chamber as the head of the vanelike piston forwardly passes the inlet port.

2. The rotary engine of claim 1 wherein the rotor member has a cylindrical rotor wall surrounded by the stator including a stator wall, said rotor member having a pair of upright parallel planar ends perpendicular to the central axis whereby the cylindrical rotor wall is of constant transverse width; wherein the transverse widths of the rotor cavity and of the vanelike piston are each substantially equal to the transverse width of the rotor; and wherein the rearwardly extending tip of the vanelike piston head portion extends across the transverse width thereof, the entire piston head rearward tip being disposed remote of the rotor wall when the piston head is in contact with the stator forwardly of the inlet port.

3. The rotary engine of claim 1 especially adapted to the utilization of relatively high-pressure noncombustible fluid introduced through the inlet conduit into the fluid chamber; and wherein the means to cause said inlet conduit to admit fluid into the fluid chamber will admit fluid therein only during those time periods when the vanelike piston rearwardly extending tip is moving forwardly of the lobe apex to reach a fluid-shutoff angular position for the vanelike piston, said piston fluid-shutoff position being located nearer to the inlet port than to the outlet port.

4. The rotary fluid-driven engine of claim 3 especially adapted to the utilization of relatively high-pressure steam fluid introduced through the inlet conduit into the fluid chamber; wherein there is a steam valve located along the inlet conduit; and wherein the means to cause said inlet conduit to admit steam into the steam chamber will admit steam therein only during those time periods when the vanelike piston is moving forwardly of the inlet port to a steam-shutoff angular position for the vanelike piston, the volume of the fluid chamber forwardly of the vanelike piston at the steamshutoff position being greater than the combined volumes of the fluid chamber rearwardly of the piston at the steam-shutoff position and the internal volume of the inlet conduit between the inlet port and the steam valve.

5. The rotary steam-driven engine of claim 4 wherein the rotor member has a cylindrical rotor wall surrounded by the stator including the stator wall, said rotor member having a pair of upright parallel planar ends perpendicular to the central axis whereby the cylindrical rotor wall is of constant transverse width; wherein the engine has a housing comprising a pair of upright parallel end plates perpendicular to the central axis, said end plates having planar walls immediately adjacent to the rotor ends, said end plates being attached to the stator member, said respective end plates each carrying a stationary gasket annularly surrounding the central axis whereby the rotor upright ends slide along the annular gaskets as the rotor rotates; wherein the transverse widths of the rotor cavity and of the vanelike piston are each substantially equal to the transverse width of the rotor; and wherein the head portion of the vanelike piston has a forwardly extending tip across the transverse width thereof, the forward extremity of the piston forward tip being offset of the stator wall major length portion toward the rotor wall.

6. The rotary steam-driven engine of claim 5 wherein the lobe apex is disposed a constant radial distance from the central axis, said constant radius arcuate lobe apex defining an angle of 5- with respect to the central axis; wherein the head portion of the vanelike piston rearwardly extending tip also transversely extends across the transverse width thereof; wherein the vanelike piston has a removably attached gasket providing the outward end extremity thereof for sliding against the stator wall; and wherein the rotor cavity at the rotor wall is recessed to accommodate the two piston tips as the piston head portion passes the arcuate lobe apex.

7. The rotary engine of claim 1 wherein the rotor member has a cylindrical outer rotor wall surrounded by the stator interior stator wall, said stator providing a portion of the stationary housing for the rotor; wherein the stator lobe apex is disposed a constant radial distance from the central axis focal reference, said constant radius arcuate lobe apex defining an angle of 5 10 with respect to the focal reference; wherein the vanelike piston with the rearwardly extending tip is resiliently radially outwardly urged from the rotor exterior wall against the stator wall including the arcuate apex inward extremity of the housing inwardly extending stator lobe; and wherein the closest proximity of the extended cavity axis to the central axis bears a ratio of one-fourth to three-fourths with respect to the constant radius of the rotor wall.

8, The rotary fluid-driven engine of claim 7 especially adapted to the utilization of relatively high-pressure steam fluid introduced through the inlet conduit into the fluid chamber; wherein there is a steam valve located along the inlet conduit; and wherein the means to cause said inlet conduit to admit steam into the steam chamber will admit steam therein only during those time periods when the vanelike piston rearwardly extending tip is moving forwardly of the inlet port to a steam-shutoff angular position for the vanelike piston, the volume of the fluid chamber forwardly of the vanelike piston at the steam-shutoff position being greater than the combined volumes of the fluid chamber rearwardly of the piston at the steam-shutoff position and the internal volume of the inlet conduit between the inlet port and the steam valve; and wherein the abruptly extending minor portion of the stator wall commencing at the arcuate lobe apex is generally parallel to the cavity axis.

9. The rotary steam-driven engine of claim 8 wherein the head end of the vanelike piston has a forwardly extending tip across the transverse width thereof, the forward extremity of the piston forward tip being inwardly offset of the stator wall major length portion.

10. The rotary steam-driven engine of claim 9 wherein the head end of the vanelike piston has a rearwardly extending tip across the transverse width thereof; wherein the vanelike piston has a removably attached T-shaped gasket providing the outward end extremity thereof for sliding against the stator wall; and wherein the rotor cavity at the rotor wall is recessed to accommodate the two piston tips as the piston head end passes the arcuate-stator lobe apex. 

1. A rotary engine having a rotor member and a stator member and comprising: A. A central shaft disposed along a central axis, said central axis serving as a focal radial reference point for the rotary engine, said central shaft being continuously rotatable in one of the two angular directions about said central axis, the said chosen angular direction being arbitrarily denominated as the forward direction; B. A rotor member attached to said rotatable central shaft whereby said rotor is directly revolvable with respect to the rotatable shaft, said rotor in perpendicular cross section to the central axis having a rotor wall concentric about the central axis focal reference, the said rotor being provided with at least one elongate cavitate portion commencing at the rotor wall and extending along a linear cavity axis which when Indefinitely extended does not intersect the central axis focal reference so that the closest proximity of the indefinitely extended cavity axis to the central axis bears a ratio of at least one-fourth with respect to the constant radius of the rotor wall, said cavitate portion terminating as an inside terminus remote of the rotor wall; C. A stator member surrounding the central axis, said stator having a peripheral stator wall that completely nonconcentrically surrounds the central axis, the major length portion of said stator peripheral stator wall being spaced a constant distance from the rotor wall and from the central axis whereby a forwardly arcuately extending fluid chamber exists within the radial space between the rotor wall and the stator wall, minor portions of said stator wall defining a stator lobe extending radially toward the rotor wall and including a lobe apex in slidable contact with the rotor cylindrical wall, said stator lobe extending abruptly from its apex at the rotor wall to the stator wall major length portion to provide a leading portion of the fluid chamber and the apex provides the leading end extremity thereof, said arcuately extending fluid chamber having a trailing position forwardly remote of said stator lobe; D. An outlet conduit attached to the stator for the exhausting of fluid from the forward trailing portion of the forwardly arcuately extending fluid chamber, said outlet conduit communicating with an outlet port within the fluid chamber trailing portion and disposed some finite angular distance forwardly of the fluid chamber leading end extremity; E. An inlet conduit attached to the stator for the introduction of fluid into the fluid chamber, said inlet conduit communicating with an inlet port within the chamber leading portion and disposed less than said finite angular distance forwardly of the fluid chamber leading end, said inlet conduit including valve means to control the amount and duration of a fluid power source for introduction into the fluid chamber; F. A resiliently depressible vanelike headed piston carried by the rotor within the elongate cavitate portion and being resiliently urged along the cavity axis from the rotor wall toward the stator wall, the vanelike piston head portion including a rearwardly extending tip that is constantly urged against the stator wall as the rotor rotates, said vanelike piston being sufficiently resiliently depressible along the cavity axis so that the piston head extremity is positionable at the rotor wall when the vanelike piston is disposed at the apex of the stator lobe; and G. Means to cause said inlet conduit valve to admit a fluid power source into the fluid chamber as the head of the vanelike piston forwardly passes the inlet port.
 2. The rotary engine of claim 1 wherein the rotor member has a cylindrical rotor wall surrounded by the stator including a stator wall, said rotor member having a pair of upright parallel planar ends perpendicular to the central axis whereby the cylindrical rotor wall is of constant transverse width; wherein the transverse widths of the rotor cavity and of the vanelike piston are each substantially equal to the transverse width of the rotor; and wherein the rearwardly extending tip of the vanelike piston head portion extends across the transverse width thereof, the entire piston head rearward tip being disposed remote of the rotor wall when the piston head is in contact with the stator forwardly of the inlet port.
 3. The rotary engine of claim 1 especially adapted to the utilization of relatively high-pressure noncombustible fluid introduced through the inlet conduit into the fluid chamber; and wherein the means to cause said inlet conduit to admit fluid into the fluid chamber will admit fluid therein only during those time periods when the vanelike piston rearwardly extending tip is moving forwardly of the lobe apex to reach a fluid-shutoff angular position for the vanelike piston, said piston fluid-shutoff position beIng located nearer to the inlet port than to the outlet port.
 4. The rotary fluid-driven engine of claim 3 especially adapted to the utilization of relatively high-pressure steam fluid introduced through the inlet conduit into the fluid chamber; wherein there is a steam valve located along the inlet conduit; and wherein the means to cause said inlet conduit to admit steam into the steam chamber will admit steam therein only during those time periods when the vanelike piston is moving forwardly of the inlet port to a steam-shutoff angular position for the vanelike piston, the volume of the fluid chamber forwardly of the vanelike piston at the steam-shutoff position being greater than the combined volumes of the fluid chamber rearwardly of the piston at the steam-shutoff position and the internal volume of the inlet conduit between the inlet port and the steam valve.
 5. The rotary steam-driven engine of claim 4 wherein the rotor member has a cylindrical rotor wall surrounded by the stator including the stator wall, said rotor member having a pair of upright parallel planar ends perpendicular to the central axis whereby the cylindrical rotor wall is of constant transverse width; wherein the engine has a housing comprising a pair of upright parallel end plates perpendicular to the central axis, said end plates having planar walls immediately adjacent to the rotor ends, said end plates being attached to the stator member, said respective end plates each carrying a stationary gasket annularly surrounding the central axis whereby the rotor upright ends slide along the annular gaskets as the rotor rotates; wherein the transverse widths of the rotor cavity and of the vanelike piston are each substantially equal to the transverse width of the rotor; and wherein the head portion of the vanelike piston has a forwardly extending tip across the transverse width thereof, the forward extremity of the piston forward tip being offset of the stator wall major length portion toward the rotor wall.
 6. The rotary steam-driven engine of claim 5 wherein the lobe apex is disposed a constant radial distance from the central axis, said constant radius arcuate lobe apex defining an angle of 5*-10* with respect to the central axis; wherein the head portion of the vanelike piston rearwardly extending tip also transversely extends across the transverse width thereof; wherein the vanelike piston has a removably attached gasket providing the outward end extremity thereof for sliding against the stator wall; and wherein the rotor cavity at the rotor wall is recessed to accommodate the two piston tips as the piston head portion passes the arcuate lobe apex.
 7. The rotary engine of claim 1 wherein the rotor member has a cylindrical outer rotor wall surrounded by the stator interior stator wall, said stator providing a portion of the stationary housing for the rotor; wherein the stator lobe apex is disposed a constant radial distance from the central axis focal reference, said constant radius arcuate lobe apex defining an angle of 5*-10* with respect to the focal reference; wherein the vanelike piston with the rearwardly extending tip is resiliently radially outwardly urged from the rotor exterior wall against the stator wall including the arcuate apex inward extremity of the housing inwardly extending stator lobe; and wherein the closest proximity of the extended cavity axis to the central axis bears a ratio of one-fourth to three-fourths with respect to the constant radius of the rotor wall.
 8. The rotary fluid-driven engine of claim 7 especially adapted to the utilization of relatively high-pressure steam fluid introduced through the inlet conduit into the fluid chamber; wherein there is a steam valve located along the inlet conduit; and wherein the means to cause said inlet conduit to admit steam into the steam chamber will admit steam therein only during those time periods when the vanelike piston rearwardly extending tip is moving forwardly of the inlet porT to a steam-shutoff angular position for the vanelike piston, the volume of the fluid chamber forwardly of the vanelike piston at the steam-shutoff position being greater than the combined volumes of the fluid chamber rearwardly of the piston at the steam-shutoff position and the internal volume of the inlet conduit between the inlet port and the steam valve; and wherein the abruptly extending minor portion of the stator wall commencing at the arcuate lobe apex is generally parallel to the cavity axis.
 9. The rotary steam-driven engine of claim 8 wherein the head end of the vanelike piston has a forwardly extending tip across the transverse width thereof, the forward extremity of the piston forward tip being inwardly offset of the stator wall major length portion.
 10. The rotary steam-driven engine of claim 9 wherein the head end of the vanelike piston has a rearwardly extending tip across the transverse width thereof; wherein the vanelike piston has a removably attached T-shaped gasket providing the outward end extremity thereof for sliding against the stator wall; and wherein the rotor cavity at the rotor wall is recessed to accommodate the two piston tips as the piston head end passes the arcuate stator lobe apex. 